共查询到20条相似文献，搜索用时 15 毫秒
1.
The work device of hydraulic excavator is considered as subject investigated, the parallel and distributing strategy to solve dynamic characteristic of complicated mechanical structure is put forward. When computing process isinefficient can be overcome by using high performance computing technology. The strategy can provide an effective approach to carry out system mechanical product generalized optimize. 相似文献
2.
Qian Zhenming Zhen Xu 《保鲜与加工》1993,(2):142-144
The .experimental system of differential Isodyne developed by authors is represented. The function and structure characteristic of the rotatable real-time loading device which is set in oil tank , the hydraulic scanning device and the device for synchronous movement of incident beam and Isodyne collector are mainly discussed. The fringe pattern of differential Isodyne in various characteristic directions and planes can be real-timely taken, by using this system. This system is able to apply to stress analyses of local effect .composite materials and structures. 相似文献
3.
The constitution, design ideas and working principles of the DDC experimental system for testing dynamic tensile stress of outside body cell using membrane variable stress wave are discussed in detail. A new design measure is put forward, i.e. using airtight liquid for transferring pressure, and a space mechanism which is made up of two moveable linking axes and controlled by DDC for producing dynamic tensile stress with variable stress wave. The space mechanism is made up of two moveable linking axes, the first axis is controlled by an alternative current servo system, at the same time it drives the modulating modulating disc, and its rotation velocity is uniform and adjustable, so the rotating velocity of the disc can be controlled. Second, the hydraulic pressure worktable is driven by step electric motor. By dynamically changing the relative position of the modulating disc and the worktable, the journey of the piston in hydraulic pressure vat can be changed accordingly. The resultant motion of the modulating disc rotation and the radial direction relative movement of the piston can create liquid pressure with variable frequency and amplitude range, and the pressure can be changed into membrane tensile stress with variable frequency and pressure amplitude range using pressure fine tuning, and muhi-path disporting pressure. The system is proved to be simple, reliable, economic and controlled expediently by the experiment conducted. 相似文献
4.
During the period of the primary contact time,there are series of recognition between the Fungal pathogens and the plant cell,which include physical and biochemical recognition.The results affect the infection directly.In the process of penetrating plant cell walls,there is not only an emzymolysis to plant cell wall,but also a mechanical squeeze to the cell wall.The latter almost trigger cell-associated defense response,such as extracellular hydrogen peroxide generation and callose doposition The complete cell wall-related defence response will be induced by mechanical signal and chemical signal together.Being to with the mammalian cell,in plant cell wall intergrin-like proteins have response to perceive the mechanical signal,which is via RGD(Arg-Gly-Asp)motif,and the plasma membrane-cell wall adhesion is required for expression of plant defense responses during fungal penetration. 相似文献
5.
Although nowadays there are many electric power measuring methods in china,some of them still have many power theft preventing bugs.To measure big and middle consumers' electric power consumption ,it is hard to prevent consumers from stealing power energy by the means of current which is difficult to be checked up by relevant products and preventing stealing power energy technology, because of using CTs to converting current.The authors especially use the example of the three phase three element active electric power meter, analyses other power theft methods and summarizes the new preventing stealing power energy technology. In accordance with the characteristic of the power measuring and on the basis of the analyzing the right method of resolving the problem,the three phase four wire system power theft preventing device can detect all sorts of stealing ,especially to the stealing by the means of current in time and accutately.This device has acquired good effect in the application of power system. 相似文献
6.
ZHANG Liang 《保鲜与加工》2002,(2):139-142
The mouse is developed with the purpose of providing reinforcement of database security for computer users, whose validity can be verified by taking advantage of the fingerprint identity, which is the uniqueness, immutability biological characteristic of human body. By one-by-one matching algorithm, rendering between pressured data and field acquisitions of finger print image, the vital heart of dactylogram verification with the mouse is realized. The mouse has been made possible by taking account of the roomy space within mouse,tiny chip patch for fingerprint identification and together with small size of available microprocessors. The mouse can be used as an normal pointing device while maintaining the capability of user identity distinguishing. The usage of this device is very easy and it is reliable. Development of this device mainly comprises of the hardware development, driver development, application software development, and the installation of network security verification center. The purpose, principle and system design of the mouse is introduced, while characteristics and applications of the device are also presented. 相似文献
7.
Wang Gongrui Zhang Hong Lu Xiao Duan Min Li Haiyun 《保鲜与加工》1995,(5):120-123
According to the especial mechanical properties of bio-soft tissue materials, we design a mechanical test system of bio-soft tissue moterials which is controlled by microcomputer and can execute the post-processing for bio-soft tissue materials. The system can solve better the problems of reliability and accuracy appearing in the test of the mechanical properties for bio-soft tissue materials,and the test is convenient as well as speedy,and provides an effective experimental means for the study of biomechanics. 相似文献
8.
Brightness level of the mad lighting should be of the mesopic vision category. But the present road lighting standard in the various countries is in the bright vision condition, this is different with the mesopic vision effect, which will bring the appraisal error into the illumination quality. Therefore, studies on the mesopic vision condition through the reaction time of the road lighting have been the front research topic. Regarding this, this article introduces the middle vision reaction time test system which independently develops to carry on the photosource light effect the research. This system can adopt different light sources to form the illumination environment under the mesopic vision, simulate road barrier ahead the car at night with varied light, and examine reaction time according to visual characteristic of driver through electronic shutter. Through regression analysis of the massive measured data, the reaction time and the background halogen brightness function expression has been fitted under the different experimental condition, thus obtains the golden photosource vision effect to be higher than the sodium lamp photosource the conclusion. In the article, the system the structure, the principle of work, the experimental technique and the data processing result has carried on the analysis and the discussion. This research results which is founded in the mesopic visual condition the visibility model provide the experimental basis, which has the very good model significance for China road lighting project concrete implementation and the actual improvement. 相似文献
9.
A method is proposed to determine the priority class of binary tree SVM. Firstly, the vibration signals of rotating machinery are colleted through a rotating machinery fault experimental platform and data acquisition system. The signals are from 5 different conditions, i.e. rotor normal, rotor unbalance, rotor misalignment, rotor bearing inner ring cracks and rotor bearing outer ring cracks. Then the signals are disposed by zero-mean and the main frequency band of the vibration signals are reconstructed to, extract the dimensionless time domain as characteristic value. Finally, the priority class of SVM 2PTMC can be determined by the correct inspection rate of parallel SVM. Training samples can be completely divided in experiments, which verifies the effectiveness of this method. 相似文献
10.
便携式烟叶厚度电子测量仪的研制 总被引：1，自引：0，他引：1
为准确测量烟叶厚度,可靠判别烤烟身份,解决长期以来依靠试验人员感官测量烟叶厚度问题,设计集高精度、小型化和便携于一体的烟叶厚度电子测量仪。该仪器包括机械测量装置和测控仪表,采用智能传感器技术以及后续硬件电路、软件系统实现烟叶厚度的测量。标定传感器,对烟叶厚度仪进行校准试验,接着对烤烟烟叶厚度进行了一天连续测量。结果显示：（1）该传感器的线性度小于1.2%;（2）仪器最大示值误差为4 μm,回程误差为2 μm;（3）叶片厚度值在9∶00左右开始下降,在13∶30-15∶30左右出现极值,在晚间叶片厚度值基本无变化。该烟叶测厚仪能够满足试验人员户外对烟叶厚度的准确测量。 相似文献
11.
By modern cybernetics, we can find out a state feedback for a linear time system, which does not change the controllability and stability of the system. But whether a state feedback for linear time system can be found out, which does ont change observability of the system or not, so far hasn't been discussed. The problem is studied according to the steady discrete time linear system, and a state feedback is found out, which does ont change the controllability, observability and stability, by relation of stability, observability and characteristic root, rank of matrix, of steady discrete time linear system; the method of how to construct the state feedback is given. 相似文献
12.
一种植物茎流传感器及其数据采集系统研究 总被引：1，自引：0，他引：1
[目的]植物茎流是研究植物蒸腾规律的重要指标,因而需要准确可靠的茎流测量设备作为支撑。[方法]本文基于热消散原理设计了一种插针式植物茎流传感器和基于MCGS软件的数据采集系统。[结果]通过模拟实验对采集系统进行了标定,测得的茎流速度与实际流速之间的误差低于0.01mm/s,表明茎流测量系统具有较高的精度和稳定性;以杨树为被测样本开展了实际测量实验,结果表明：日出后,随着气温的升高茎流速度开始缓慢上升,中午12:00至15点期间达到峰值并保持较高速率,此后茎流速度缓慢下降,日落后19:00左右开始迅速下降并保持较低茎流速率直至次日。[结论]以上实验结果表明该系统能准确反映植株茎流的日变化规律,且稳定性较好,可为植株耗水性及蒸腾规律的研究提供设备支撑。 相似文献
13.
According to the transmission way of information flow of gear noise ,we presentthe method of solid state acoustic detection, Noticeing transmission characteristic of the acoustic information flow, we develop and deduce the time domain seperating method. The experimental resultshows that the method can identify gear failure and also can extract the acoustie information flow ofwhich can correctly reflect,the gear moving characteristic , It is very useful to monitor the gear statecharacteristic. 相似文献
14.
The impulse value of a impulse mechanism has a notable influence on the dynamics capability of impulse variable speed device. Basing on this point, the authors take crank-rocker mechanism in series with slider-crank mechanism as impulse mechanism when we design the impulse variable speed device. The link used to adjust the speed is applied in slider-crank mechanism which has no quick-return characteristic, so the advance-to return-time ratio keeps stable when we adjust its speed. The speed fluctuation also keeps invariable. The new method overcome the default that this kind of impulse variable speed device has a notable speed fluctuation. At the same time, ADAMS software is used to optimize and show the real motion law. From the simulation result we can get the speed fluctuation is down to 18% in the whole process. The change of speed fluctuation is down to 1%. The result is better than other mechanism like this category. 相似文献
15.
Under a certain electric field strength of steep pulse, plenty of micropores occur in the cell membrane. The number and diameter of micropore increase rapidly with the increase of electric field strength, the membrane breaks and the cell dies at last. This phenomenon is called as irreversible electrical breakdown (IREB). To research IREB of tumor cell, integrated with power electronics and conventional high voltage pulse generator, an energy-controllable steep pulse apparatus for tumor treatment is developed. The peak value, width, frequency and rise time of the output pulse can be adjusted independently, so the energy of the output pulse can be easily controlled. The apparatus is applied in cell experiment after a detailed analysis of its operating principle and debugging in laboratory. The experiment results show that the device works steadily and satisfies the demand of medical experiment. 相似文献
16.
土荆芥挥发油化感胁迫对蚕豆根尖SOD和POD同工酶的影响 总被引：1，自引：1，他引：0
旨在了解土荆芥挥发油对受体植物抗氧化酶系统的影响,为阐明土荆芥的化感作用机制提供理论依据。通过模拟淋溶和挥发2条途径,分别以不同剂量挥发油处理受体植物蚕豆幼根,电泳后比较根尖超氧化物歧化酶(SOD)和过氧化物酶(POD)同工酶谱的变化。结果表明：在淋溶途径中,细胞内SOD活性明显受该挥发油抑制,处理48 h后POD同工酶谱有POD7特征性强带出现;在挥发途径中,该挥发油对SOD同工酶的活性则表现为促进效应,处理浓度较高或时间较长(24 h,20 μL;48 h,15~20 μL;72 h,10~20 μL)时,POD同工酶谱有POD6特征性强带的表达。此外,SOD同工酶谱带变化主要为酶带的强度改变,POD同工酶谱带变化主要为酶带的数量增减。由此推测土荆芥挥发油可影响蚕豆根尖细胞SOD和POD同工酶基因的表达,其中POD同工酶基因的响应可能比SOD更为敏感。 相似文献
17.
Based on the geometrical optics and vector diffraction theory, mode converter is studied the output mode of which is converted to line polarization Gauss beam of gyrotron and high power microwave device, the radiation characteristic of quasi-optical mode conversion is simulated. Quasi gauss mode HEll can be realized with Vlasov launcher and quasi-optical reflector. 相似文献
18.
YAO Chen-guo SUN Cai-xin XIONG Lan MI Yan WANG Shi-bin Under the State Ministry of Education Chongqing University Chongqing Chin 《保鲜与加工》2004,(6):32-35
The basic characteristic of electric field is that the substance in the field is in operation by the stress. Under steep pulsed electric fields, there is strong distribution of electric fields on the inside and outside surfaces of cell membrane. In virtue of the difference of the permittivity among membrane, cytoplasm and extracellular medium, there must be the electric field stress on the surface of the membrane. The calculation results showe that cell membrane is stressed from two directions of cytoplasm and extracellular medium under external electric fields. The stress on tumor cell membrane is greatly larger than normal cell membrane, so the tumor cell is more sensitive than normal cell. Tumor cell membrane certainly will be destroyed by electric field stress, then its survival environment and germ plasm will be injured and accordingly the cell will be damaged. 相似文献
19.
Aiming at confined concrete with stirrups and carbon fiber reinforced plastic(CFRP) respectively, the major influence factors of mechanical behavior of confined concrete under axial compression were studied based on reported experimental data. The equations for calculating the peak stress, peak strain and ultimate strain were proposed respectively for confined concrete with stirrups and CFRP. Contrastive analysis shows that the behavior of confined concrete with stirrups is better than confined concrete with CFRP in low characteristic value, whereas the conclusion is contrary in high characteristic value. 相似文献
20.
在油气钻井工程中,由岩石蠕变引起的井眼缩径或井壁坍塌时有发生,本文基于能量守恒定律分析岩石蠕变的3个阶段,阐述传统的蠕变模型难以研究岩石加速蠕变阶段的原因。为此,在西原模型的基础上串联了一个绕组元件,建立改进西原模型及相应的本构方程。根据油气开发过程中所钻遇地层部分岩心的蠕变实验数据,对建立的改进西原模型进行验证,表明该模型能够很好地反映出岩石的蠕变特性,尤其是在岩石所受荷载大于长期强度的情况下,对凸显岩石加速蠕变阶段效果明显。该改进西原模型的提出可为进一步揭示岩石蠕变的客观规律提供理论依据。 相似文献